Synthesis of mesoporous pseudoboehmite and alumina templated with 1-hexadecyl-2,3-dimethyl-imidazolium chloride

Li, Dian Yi; Lin, Yi; Li, Yu Ching; Shieh, Dong Lin; Lin, Ja‐Chen

doi:10.1016/j.micromeso.2007.04.009

Cited by 57 publications

(33 citation statements)

References 22 publications

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“…For the γ-AlOOH surface before any reactions (curve a 1 ), the two bands with wavenumbers 3,404 and 3,089 cm −1 are attributed to -OH bonds, and the two bands at 2,099 and 1,639 cm −1 are attributed to H-O-H bonds. The band at 1,072 cm −1 corresponds to the δ s Al-O-H mode of boehmite and the bands at 884, 740, 621, and 479 cm −1 are attributed to the Al-O bonds of boehmite (Li et al 2008). For the γ-Al 2 O 3 surface before any reaction (curve b 1 ), some -OH and H-O-H bands could still be identified in the spectra but had lower transmittance intensities.…”

Section: Fourier Transform Infrared Spectroscopymentioning

confidence: 99%

Dechlorinating transformation of propachlor through nucleophilic substitution by dithionite on the surface of alumina

et al. 2012

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Purpose The aim of this study was to evaluate the roles of aluminum-based minerals, especially their surface Lewis acid sites (LASs), on the transformation and fate of chloroacetanilide herbicide contaminants when nucleophilic reagents are present. Materials and methods Batch experiments were used to study propachlor transformation processes under different reaction conditions. The surface bonding of aluminas before and after interacting with propachlor and dithionite were characterized by Fourier transform infrared (FTIR) spectra. The LASs on different aluminas, acting as the key role for accelerating the propachlor transformation, were analyzed by pyridine adsorption/FTIR spectroscopic technique. Results and discussion Rates of dithionite-initiated propachlor dechlorination were increased in the presence of aluminas. Transformation efficiencies of propachlor on different aluminas were found to be as γ-Al 2 O 3 >γ-AlOOH>α-Al 2 O 3 . A higher reaction temperature, higher pH, and higher alumina dosage can further increase the propachlor dechlorination rate.The addition of citric acid may block the active sites on alumina and reduce propachlor transformation by dithionite. FTIR and pyridine adsorption/diffuse reflectance Fourier transform infrared spectroscopy indicated that Al-S and Al-O bonds on the LASs of alumna play a key role in accelerating propachlor transformation. Conclusions LASs on alumina surfaces can effectively accelerate the propachlor transformation by dithionite. The strong electron accepting ability of LASs gives dithionite a favorable affinity to form surface sulfur compounds, which are stronger reductants and nucleophilic reagents for propachlor dechlorination. The intensities of LASs on alumina surfaces can be used to control the rate of propachlor transformation by dithionite.

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Section: Fourier Transform Infrared Spectroscopymentioning

confidence: 99%

Dechlorinating transformation of propachlor through nucleophilic substitution by dithionite on the surface of alumina

et al. 2012

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“…For the original g-AlOOH with no reactions (curve a 1 ), the bands at high wave numbers of 3304 and 3090 cm À1 (two split broad bands) are attributed to -OH bond stretching vibration, whereas the bands at 2101 and 1640 cm À1 are attributed to H-O-H bond stretching vibration. The band at 1072 cm À1 corresponds to the d s Al-O-H of boehmite, and the four bands at 884, 740, 623, and 488 cm À1 are attributed to the Al-O band stretching vibration of boehmite [33]. For g-Al 2 O 3 sample with no reactions (curve b 1 ), the H-O-H and -OH bonds were also found but with much lower transmittance intensities in the spectra.…”

Section: Metolachlor Transformation Under Different Phmentioning

confidence: 93%

Heterogeneous Nucleophilic Transformation of Metolachlor by Bisulfide on Alumina Surface

Wei

Liu

et al. 2013

CLEAN Soil Air Water

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The present research elucidates the accelerating effect of alumina minerals on metolachlor transformation using sulfur nucleophiles and also determines the metolachlor transformation mechanisms in the heterogeneous reaction systems. Metolachlor transformation was first systematically investigated under different conditions. Then, the Fourier transform infrared (FTIR) spectra were used to characterize the changes in the surface bonds of the aluminas. The transformation products were qualitatively identified using LC/MS. The results showed that bisulfide can produce efficient metolachlor transformation rates, and the presence of the aluminas can further accelerate the transformation by achieving complete transformation in <21 days. In addition, a higher pH and higher bisulfide concentration are more favorable for metolachlor transformation. When normalized to the surface area, the metolachlor transformation rates were found to follow the order of a-Al 2 O 3 >g-AlOOH>g-Al 2 O 3 in the presence of different aluminas. FTIR results indicated that the enhancement of metolachlor transformation rates by bisulfide with aluminas can be attributed to the surface active nucleophiles on alumina surfaces formed through Al-S and Al-O bonds. The substitution of chlorine on the metolachlor followed the S N 2 mechanism by bisulfide with accelerated rate through mediating the heterogeneous reactions with aluminas.

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“…All the AlO and SiO related vibrations are known to appear only in the 1200400 cm ¹1 region. 21) The distinct peak at 1069 cm ¹1 is characteristic of SiOSi vibration while the shoulders appearing at higher and lower side of this absorption band indicate the presence of AlOSi bonds through cross-condensation of boehmite and silica. 22) The PO takes proton from hydrated aluminum, and undergoes irreversible ring-opening reaction by the nucleophilic attack of the chloride ion.…”

Section: Ftir Analysismentioning

confidence: 99%

Preparation and characterization of monolithic Al2O3–SiO2 aerogel

Chen

Sui²,

Zhou³

et al. 2016

J. Ceram. Soc. Japan

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Al 2 O 3 SiO 2 aerogel was prepared through mixed solgel process and ethanol supercritical drying technology using aluminum chloride hexahydrate (AlCl 3 ·6H 2 O) and tetraethoxysilane (TEOS) as precursors. Under the condition of the propylene oxide used as gelation initiators, during the process, a kind of Al 2 O 3 SiO 2 aerogel with porous and large specific surface area were achieved in our experiments. Structures and properties of Al 2 O 3 SiO 2 aerogel are investigated by means of X-ray Diffraction, Nitrogen adsorption/desorption analysis, Scanning Electron Microscopy, Fourier Transform Infrared Spectroscope, and Thermogravimetry-Differential Thermal analysis. The results showed that the Al 2 O 3 SiO 2 aerogel with the mole ratio of Al/Si = 3/1 possessed better heat-insulation performance and high-temperature stability. And it possessed a porous network structure made up of leaf shape particles. At the same time, Al 2 O 3 SiO 2 aerogel showed a low density of 0.071 g/cm 3 at room temperature, specific surface areas of 708 m 2 /g at 600°C, as well as 255 m 2 /g at 1200°C. The Al 2 O 3 SiO 2 aerogel is the polycrystalline boehmite (£-AlOOH) phase at room temperature. As the temperature growing, it transferred to £-Al 2 O 3 at 600°C, and mullite phase at 1200°C.

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Synthesis of mesoporous pseudoboehmite and alumina templated with 1-hexadecyl-2,3-dimethyl-imidazolium chloride

Cited by 57 publications

References 22 publications

Dechlorinating transformation of propachlor through nucleophilic substitution by dithionite on the surface of alumina

Dechlorinating transformation of propachlor through nucleophilic substitution by dithionite on the surface of alumina

Heterogeneous Nucleophilic Transformation of Metolachlor by Bisulfide on Alumina Surface

Preparation and characterization of monolithic Al<sub>2</sub>O<sub>3</sub>–SiO<sub>2</sub> aerogel

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Synthesis of mesoporous pseudoboehmite and alumina templated with 1-hexadecyl-2,3-dimethyl-imidazolium chloride

Cited by 57 publications

References 22 publications

Dechlorinating transformation of propachlor through nucleophilic substitution by dithionite on the surface of alumina

Dechlorinating transformation of propachlor through nucleophilic substitution by dithionite on the surface of alumina

Heterogeneous Nucleophilic Transformation of Metolachlor by Bisulfide on Alumina Surface

Preparation and characterization of monolithic Al<sub>2</sub>O<sub>3</sub>&ndash;SiO<sub>2</sub> aerogel

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Preparation and characterization of monolithic Al<sub>2</sub>O<sub>3</sub>–SiO<sub>2</sub> aerogel